Causes and Symptoms of Vaginal Yeast Infections in Women

What is a vaginal yeast infection?

Many microbes can cause a vaginal infection. When it’s caused by bacteria, it’s called bacterial vaginosis. A parasite called Trichomonas can also cause vaginitis. In this case, the infection is sexually transmitted.

Vaginal yeast infections are caused by a single-celled microscopic fungus (a yeast called Candida albicans) found on the skin and mucous membranes.

How do you get a vaginal yeast infection?

You don’t “catch” a yeast infection. It’s not an infection that’s transmitted from person to person. In fact, everyone has yeasts that live naturally on their body.

Yeast is part of a woman’s normal vaginal flora. When all is well, they live in harmony with various bacteria and cause no symptoms. If this harmony is disrupted, these yeasts (or bacteria in the case of vaginosis) can take advantage of the situation to multiply more than usual and cause an infection.

Many situations can encourage the growth of yeast, for example:

• hormonal changes, such as pregnancy or perimenopause;
• estrogen therapy (for contraception or menopause);
• antibiotic therapy;
• high blood sugar in diabetics;
• a weakened immune system.

Is a vaginal yeast infection a sexually transmitted infection (STI)?

No, vaginal yeast infections are not sexually transmitted. However, sexual activity can increase the risk of yeast infections because sexual intercourse can disrupt the vaginal flora.

Men can get a yeast infection in the folds of the foreskin, but this is less common than vaginitis in women.

What are the symptoms of a vaginal yeast infection?

When a vaginal yeast infection occurs, symptoms appear not only in the vagina but also in the vulva. This is why it is sometimes called vulvovaginitis.

Any of the following symptoms may be associated with a yeast infection:

• itching, sometimes severe, in the vulva or vagina;
• irritation or burning sensation in the vulva or vagina;
• redness or swelling of the vulva or vaginal walls;
• pain or discomfort when urinating or having intercourse;
• odourless whitish vaginal discharge, thicker than usual (looks like cottage cheese).

Symptoms can vary from one woman to another and from one episode to the next.

If you have a fever, if the discharge is coloured or has an unpleasant smell (e.g., fishy), if you have abdominal pain, or if you have blood in your urine, it may not be a vaginal yeast infection. It’s important to see a healthcare professional who can determine the cause of your symptoms and prescribe the right treatment.

How is a yeast infection treated?

If the symptoms are mild and the woman is otherwise healthy, treatment of the vaginal yeast infection may not be necessary. Her immune system will work to re-establish the vaginal flora. These milder infections often go unnoticed because the symptoms resolve within a couple of days.

However, if the symptoms are bothersome or the woman has health problems that affect her ability to fight the infection, treatment is recommended to speed recovery.

The treatment for a yeast infection is an antifungal medication that kills the yeast. Depending on the product used, treatment may last 1 to 7 days. Symptoms usually improve within 24 to 48 hours.

Some antifungal medications are used locally in the vagina to treat the infection. They come in different forms, such as pre-filled cream applicators, ovules or suppositories that are inserted into the vagina. There is also an antifungal medication that can be taken by mouth and requires only a single dose. A cream can also be applied to the vulva to relieve external symptoms.

In most cases, all these products are equally effective. The choice depends mainly on the woman’s preferences. 

In Canada, these antifungals can be prescribed by a healthcare professional, including pharmacists in most provinces. Some products are also available without a prescription in pharmacies.

It is recommended that women see a healthcare professional when they first experience symptoms of a vaginal yeast infection to make the proper diagnosis. If further episodes occur, they will usually be able to recognize the symptoms and treat them with an over-the-counter antifungal.

Other types of vaginitis require medical evaluation and prescription treatment.

Antibiotics are ineffective in the treatment of yeast infections because they only kill bacteria. In fact, they may increase the risk of a yeast infection by killing bacteria that help maintain the balance of the vaginal flora.

What can you do to reduce your risk of vaginal yeast infections?

To reduce the risk of yeast infections, you can take a few simple steps.

• Avoid unnecessary antibiotic treatment, e.g., for bronchitis.
• Because yeast thrives in a moist environment, keep the external genital area clean and dry. Wash the area with a mild, fragrance-free soap and pat dry with a towel.
• Do not use douches. These products can disrupt the vaginal flora and increase the risk of yeast infections.
• Wear breathable fabrics such as cotton. Remove panties at night.
• Avoid products that may irritate the vaginal area or disrupt the vaginal flora, such as massage oils or spermicides. Use water-based lubricants to help with vaginal dryness.
• For some women, a yeast infection tends to occur after having sexual intercourse. If this is your case, wash your genitals after each sexual encounter.

What can you do about recurring yeast infections?

Nearly 50% of women will have at least 2 vaginal yeast infections in their lifetime. A small proportion of these women (about 5%) may have very frequent episodes. When there are more than 4 episodes in a 12-month period, yeast infections are considered recurrent.

In these cases, it’s important to see a healthcare professional who can perform a complete medical examination to confirm it’s a yeast infection and not another health problem, such as a sexually transmitted infection. 

Treatment is prescribed to treat the new episode, but also to reduce the risk of future yeast infections (e.g., antifungals taken weekly or monthly, boric acid taken at the start of each period).

Your pharmacist is here for you!

In most provinces, pharmacists can prescribe an antifungal to treat vaginal yeast infections under certain circumstances. If you think you have a yeast infection, talk to your pharmacist. They can answer your questions, prescribe an antifungal or recommend an over-the-counter treatment, or refer you to the right resources if they think you need medical help.